The present invention relates to a waste heat recovery system for combustion engines and a method of controlling said waste heat recovery system.
The continued reliance on high-cost diesel hydrocarbon fuel and the implementation of increasingly strict emission controls have had, and will continue to have, a significant impact on our society. These impacts include an increase in the cost of transporting goods (which, in turn, leads to increases in retail prices, i.e., inflation), increased global tensions (as a large fraction of known oil reserves are located in tumultuous regions of the globe), and increased cost of power generating systems, including vehicles, (due to the need to add ever more complex, and costly, exhaust treatment systems).
These impacts have not gone unnoticed and a variety of inventions have been disclosed to address them. For instance, hybrid-electric vehicles are currently gaining in popularity due to the increased mileage they provide. This is achieved by adding a temporary energy storage device, e.g. a battery, to the vehicle and using this device to decouple power production from power consumption, allowing each to operate in its optimal regime.
Another area that has received some focus is the extraction of additional useful energy from the ‘waste’ energy streams discharged from internal combustion engines. Typically, between 55% and 75% of all the heat energy of the fuel consumed in an internal combustion energy is not converted into useful energy and is dissipated to the surrounding environment. Given the magnitude of the energy entrained in these waste heat streams, a means for extracting additional useful energy from internal combustion engines is needed.